The subject matter disclosed herein relates generally to distance measuring devices.
In fixed-pipe process plants of the food and pharmaceutical industry, pneumatic valves are used as                (a) single-seated blocking valves for simple blocking at pipeline intersections;        (b) single-seated two-way valves for combining products from two pipelines in one pipeline and for dividing one pipeline into two pipelines; and        (c) double-seated valves for mix-proof separation of adverse products at pipeline intersections.        
The precise function of the valves is described e.g. in the company brochures of the companies GEA/Tuchenhagen and Alfa Laval.
In order to control the process it is necessary to detect the position of the valves. For this purpose sensors such as potentiometers, LVDTs or just simple reed switches are used. All of these sensors are complex to fit, are partially subject to mechanical wear and tear, and require additional external space.